A technique for the correction of long-term magnetic flux integrator drift

In the framework of magnetic measurements in particle accelerators, the problem of the drift due to integration of a voltage offset causes a lack of stability, which is inadequate for long-term measurements. In this paper, a new approach for the modelling and correction of long-term drift in integrators is discussed. In particular, a feed-forward drift correction method has been developed analytically and tested using experimental data taken from an existing real-time magnetic measurement system. Among all the sensors, NMR was chosen for the integration constant due to its accuracy (10
^-6
) and the Metrolab PT2026 NMR teslameter has been tested successfully as a novel kind of quasi-DC field marker. The combination of feed-forward correction and PT2026 as a marker will allow the future real-time magnetic measurement systems to meet the very strict specification of 1 μT field stability over durations of the order of minutes. In certain cases, such as in ELENA, this method offers a way to reduce by three orders of magnitude the drift-induced field error with respect to the existing system.